Browsing by Author "Kumar, S.A."

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    Comparative Analysis of Physicochemical and Sensory Attributes of Mature and Immature Tumid Venus Clam (Gafrarium tumidum) in Different Locations of Jaffna Lagoon, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2018) Jeyaamuthan, S.; Kumar, S.A.; Jayawardana, J.M.D.R.; Thushari, G.G.N.; Jayasena, D.K.D.D.
    Tumid Venus clam (Gafrarium tumiduni) is one of the dominant and readily available coastal bivalves consumed by local residents in Jaffna district of Sri Lanka. Scientific data on physicochemical and sensory attributes of this species is however scarce. Therefore, the objective of this study was to determine physicochemical and sensory attributes of Tumid Venus clam in four different sites of Jaffna lagoon at two different maturity stages. Randomly collected 200 clams from each different sites of Jaffna lagoon: Karainagar (9.7481°N, 79.8829°E), Mandaitivu (9.6165°N, 79.9920°E), Kayts (9.6526°N, 79.9081°E) and Navanthurai (9.6687°N, 80.0007°E) were graded into two maturity stages as mature (100 clams >35 mm in each location) and immature (100 clams <35 mm in each location) based on the shell length. The composite flesh samples were then subjected to analysis of physicochemical and organoleptic attributes using standard analytical protocols. Results revealed that there was a significant difference in color a* (redness), b* (yellowness), L* (lightness), pH value, water holding capacity, moisture and ash contents with the location as food availability is changed with inhabiting region (p<0.05). However, maturity stage had significant effects only on color a*, b* and L* values and water holding capacity (p<0.05). Based on the sensory evaluation, the appearance and taste of cooked clams were significantly varied with the location and maturity stage due to qualitative & quantitative changes of food items under different environmental conditions and variable nutritional requirements with maturity level (p<0.05). The highest consumer acceptance was recorded for immature bivalve samples from Navanthurai. In conclusion, current study showed the suitability of low cost bivalve resources as a substitute for conventional, expensive seafood sources. Furthermore, location and maturity stage had a significant effect on physiochemical and sensory attributes of Tumid Venus clam.
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    Optimization of a Ribonucleic Acid (RNA) Extraction Protocol for Viruses in Clinical Samples for Disease Diagnosis
    (Uva Wellassa University of Sri Lanka, 2016) Kumar, S.A.; Gunathilaka, P.A.D.H.N.; Rodrigo, W.W.P.; Athapaththu, A.M.M.H.
    Ribonucleic acid (RNA) is a polymeric molecule. It is implicated in coding and gene expression. Some medically important organisms such as viruses have only RNAs as their inherent material. To detect the viral diseases using molecular biological methods, it needs extraction of RNA from body fluids. There are several methods of RNA extraction, which require costly reagents and kits. Hence, the objective of this study was to optimize a low cost, in-house protocol for RNA extraction of viruses in clinical samples in order to facilitate disease diagnosis. Clinically confirmed blood samples, which were positive for Dengue Virus by NS1 antigen test, were taken for optimization of the two protocols. Two different RNA extraction protocols were used for the study to identify the most appropriate and reliable method with high efficiency. Trizol reagent, which was prepared in house was used in both protocols. Extracted RNA from both the protocols were quantified at 260 nm using a spectrophotometer. The RNA amount quantified from the spectrophotometer showed a result of 64 and 72 ng/ul from first and second protocols, respectively. In the first protocol, all the procedures were undertaken at room temperature (27-35 °C) but generally RNA is not stable at the room temperature. Therefore, RNA might have degraded due to lack of optimum conditions during the incubation, centrifugation and storage periods. In addition, if the RNA pellets were air dried completely, it becomes insoluble in RNase free water. Therefore, extracted RNA might not have been re-suspended completely in the solution. Those identified drawbacks were adjusted in the second protocol. Further, incubation temperature and time period (4 °C and 30 minutes) and centrifugation time (15 minutes), were modified to achieve stabilization, complete precipitation of RNA molecules and to prevent degradation by RNases. According to the above discussed facts, this study reveals that the second protocol is more suitable for RNA extraction ofviruses in clinical samples. Keywords: Ribonucleic Acid (RNA), Virus, Extraction